The visual system of fish continues to grow throughout life and is capable of regeneration after damage. It is also capable of considerable neuronal plasticity which allows the formation of various abnormal patterns of connection between the retina and the primary visual center in the brain, the optic tectum. One of the aims of this project is to show the extent to which adaptive visual behavior to fish, as revealed by visuomotor periemtry, can be restored after optic nerve regeneration and rearrangement of the visuotopic map. To the extent that normal function is restored, visual deprivation experiments will be done to assess the role of visual experience, while electrophysiological and neuroanatomical studies will be done to reveal the patterns of connections between retina, optic tectum and other brain centers involved in vision that could underlie the observed behavior. Similar beharioral, electrophysiological and anatomical methods will be applied to examine the extent to which visual deprivation and the blocking of neural activity can influence the formation of visuotopic mapping during growth and regeneration. The retinotectal systems of fish and amphibia provide a very valuable model for studying the mechanisms of neural regeneration and plasticity, mechanisms which may also operate in mammals, including man. Using the same model system, this research aims to show the conditions under which regeneration and plastic modification can lead to adaptive function.